Multi-layer printed circuit boards (PCBs) include many layers of conductive material, such as copper, separated by layers of insulating material. Many of these PCBs include power and ground layers formed from planes of copper, where the entire plane is dedicated to either power or ground. Digital integrated circuit (IC) devices mounted to the PCBs connect to these power and ground planes to establish electrical current, or power, in the IC devices.
When IC devices in a PCB switch ON (ie., transition from the logic xe2x80x9c0xe2x80x9d state to the logic xe2x80x9c1xe2x80x9d state), the devices suddenly begin drawing current from the power bus. Likewise, current flow in the IC devices stops suddenly when the devices switch OFF. When high-speed IC devices are involved, these sudden surges in current create high frequency transients and electrical noise on the power bus. In general, this electrical noise manifests itself in two ways: (1) As radiated electromagnetic energy that escapes the PCB and interferes with the operation of other system components; and (2) as internal noise that disrupts the function of other circuits on the PCB.
A printed circuit board includes a power layer for use in providing electrical power to circuit components and a ground layer for use in carrying electrical current away from the circuit components. A loss element connects electrically between the power layer and ground layer to suppress electrical noise caused by changes in current flow in the circuit components.
Other features and advantages will become apparent from the description and claims that follow.